1. Field of the Invention
The present invention relates to a wireless terminal device having a plurality of communication units and a control method thereof.
2. Related Art
The communication of data is performed in accordance with a predetermined protocol (e.g., TCP/IP (Transmission Control Protocol/Internet Protocol)) between electronic devices carrying out communication via a network (e.g., Japanese Unexamined Patent Application, Publication No. H5-207023).
In addition, recent electronic devices have a function of setting an interval to send reception confirmation of data to an electronic device on the sending side (hereinafter referred to as RWIN (Receive Window)) when sending and receiving data via TCP/IP.
Herein, it is configured so as to frequently send reception confirmation of data to an electronic device on a sending side in a case of RWIN being too small compared to the speed of a communication line of the network. When this is done, since the electronic device on the sending side does not send subsequent data until reception confirmation is sent, the time required for the round trip of reception confirmation is all time loss, and the communication speed will slow by this amount.
On the other hand, in a case of RWIN being too large compared to the speed of the communication line of the network, the time required to resend when incorrect data is flowing lengthens, and the communication speed slows in this case as well.
Therefore, it has been desired for the electronic device on the receiving side to appropriately set the set value of RWIN while taking into consideration the speed of the communication line of the network.